Practice Arena

Python Coding Challenges

Write real Python in the browser. Instant feedback. From beginner to expert.

925 challenges 556 easy 323 medium 46 hard
All Easy Medium Hard
All Python Basics Strings & Text Lists & Arrays Dicts & Sets Functions & Closures OOP & Classes Data Structures & Algorithms Advanced Python Iterators & Generators Decorators & Context Managers Error Handling & Exceptions Regular Expressions Math & Number Theory Bit Manipulation Dynamic Programming Trees & Binary Trees Graphs & Graph Algorithms Recursion & Backtracking Greedy Algorithms Binary Search Two Pointers & Sliding Window Stacks & Queues Heaps & Priority Queues Linked Lists Matrix & 2D Arrays Datetime & Time Calculations Data Formats & Parsing SQL & SQLite Numpy & Vectorized Computing Cryptography & Hashing
Dynamic Programming hard

Palindrome Partitioning Minimum Cuts

Given a string, return the minimum number of cuts needed such that every substring in the partition is a palindrome.

dynamic-programming palindrome strings
+40 pts 35m
Dynamic Programming hard

Egg Drop Puzzle

Given k eggs and n floors, compute the minimum number of attempts required in the worst case to find the highest safe floor.

dynamic-programming optimization classic-puzzle
+45 pts 35m
Graphs & Graph Algorithms hard

Minimum Cut

Given an undirected graph in adjacency-list form, return the size of the minimum edge cut that disconnects the graph.

graphs max-flow min-cut
+40 pts 35m
Graphs & Graph Algorithms hard

Swim in Rising Water

Find the minimum time needed to swim from the top-left to the bottom-right of a grid where water level rises and you can only move to cells with elevation ≤ current time.

graph minimax priority-queue
+30 pts 20m
Recursion & Backtracking hard

Remove invalid parentheses

Given a string with parentheses and letters, return all valid strings after removing the minimum number of invalid parentheses.

backtracking parentheses string
+45 pts 40m
Greedy Algorithms hard

Patching Array

Given a sorted array of positive integers and a target n, find the minimum number of patches to make every number from 1 to n representable as a subset sum.

greedy arrays prefix-sums
+40 pts 30m
Two Pointers & Sliding Window hard

Minimum Window Substring

Implement a sliding window algorithm to find the minimum window substring containing all characters of a given pattern.

sliding-window two-pointers strings
+45 pts 35m
Two Pointers & Sliding Window hard

Minimum Window Subsequence

Given strings s and t, return the minimum window substring of s that contains t as a subsequence, or empty string if none exists.

sliding-window recursion dynamic-programming
+40 pts 35m

Showing 1–8 of 8 challenges · hard

Guide: free Python coding challenges

Practice Python by solving problems

PythonSkillset challenges are hands-on coding exercises from beginner to advanced. Open a challenge, read the problem, write Python in the split-pane editor, and run tests with Pyodide — no install required.

How to use the arena

  1. Pick a category — basics, algorithms, strings, and more
  2. Open a challenge, read the statement, and edit the starter code
  3. Run tests, fix failures, then try a related quiz or tutorial lesson

Challenges vs tutorials and quizzes

Challenges test what you can build under constraints. For guided teaching, use our Python tutorials. For quick checks, try quizzes or copy snippets from code samples.